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Increased whole body glutamine turnover in cancer is not matched by increased hindquarter glutamine release
A722
AGA ABSTRACTS
GASTROENTEROLOGY, Vol. 108, No. 4
INCREASED WHOLE BODY GLUTAMINE TURNOVER iN CANCER IS NOT MATCHED BY INCREASED HINDQUARTER GLUTAMINE RELEASE Lde Blaauw, NEP Deutz, MF von Meyenfeldt, Dept of Surgery, Fac II, Univ Limburg. Maastricht,The Nether!ands.
MOTILIN IN HUMAN M I L K : IDENTIFICATION AND STABILITY DURING DIGESTION. P.De Clerca, S.Springer', T,L,Peeters. Gut Hormone Lab, K.U.Leuven, Leuven, Belgium and "Paediatric Unit, University Hospital, Leipzig, Germany.
Glutamine (Gin) is mainly produced by muscle. Cancer cells consume Gin at a high rate for energy ~nd nucleotide production and may disturb Gin interorgan metabolism. Aim of this study was to see whether whole body Gin and protein metabolism were matched by sufficient Gin release of muscle tissue. Methods A MCA-induced sarcoma was implanted subcutaneously in Lewis rats (±250 gr). Rats were studied when the tumor was 5-15% (ST) or 15-25% (L'r) of the body weight. Control rats were sham implanted. Under anesthesia a constant infusion of para-aminohippuric acid, L-[3,4-3H]-GIn and L-[2,6-3H]Phenylalanine was given. At steady state, hindquarter bloodfiow, arterial and venous substrate concentrations and amino acid specific activity were measured to calculate whole body Gin and protein turnover, hindquarter Gin release and hindquarter muscle protein turnover, Results No anorexia occurred and carcass weight was not significantly different between the groups. Arterial Gin levels decreased from 657±26 (control) to 611±22 (ST) to 558±13 pM (P<0.05) in the LT group. Table Whole body Gin turnover increased in the LT group. Protein turnover increased in the ST and LT group. Hindquarter release of glutamine increased in the ST group but decreased again in the LT group. A net protein loss was seen (Phe release) in the ST possible due to increased protein breakdown rates with unchanged protein synthesis rates. Net protein breakdown was unchanged in the LT group.
The presence in human milk of several brain-gut peptides and of peptide g r o w t h factors has been documented and a role o f these peptides in early development has been suggested. We have studied the presence and stability of motUin in human milk. Milk and plasma samples were collected from 14 mothers, and motilin was measured by radioimmunoassay. Plasma levels were 416 ± 37 pg/ml. In 8 defatted milk samples the motilin level was 105 ± 14 pg]ml, in the 6 others levels were above i 0 0 0 pg/ml but dilution Curves were non-linear. After solid-ph~ise extraction milk levels were 108 ± 21 pg/ml in 13 samples, i n 1 sample the dilution curve w a s Still non-linear. The presence of motilin was certified by the partial purification of motilin from human milk. A 500 ml amount of human m i l k was defatted, absorbed on a Cls.column and eluted with 50% acetonitrile in 10 mM HCI. The eluate was tyophilized and subjected to gel chromatography and HPLC. In b o t h instances the peak of immune-reactivity eluted at the same position as human motilin. The stability of motilin after ingestion w a s studied by incubating 12sl-nlelS-porcine motilin with gastric a n d intestinal juice obtained from a newborn (diluted 1:10). Incubations were performed at 3 7 ° C at pH 1.8, 3.2 and 5.8 for the gastric fluid and at pH 7.4 for duodenal fluid. Afte r different t i m e intervals ( 5 , 10, 20, 30 m i n ) i n t a c t motilin Was precipitated with trichloroacetic acid, and the radioactivity of t h e supernatans was determined: Motilin was rapidly degraded by gastric juice. The breakdown was greatest at pH 3.2 (77.8 % after 30 min) and lowest a t 15H 5 . 8 ( 3 9 . 1 % ) , the pH after milk feeding in neonates. Degradation by intestinal juice at pH 7.4 was also very rapid (73.9 % ). Human milk and BSA inhibited partially, casein inhibited totally the gastric digestion at pH 3.2 (36.6%, 53.2% and 5 . 0 % d e g r a d a t i o n after 30 mm, respectively). Digestion by intestinal juice was not affected by human milk and BSA (77.2 and 80.2 %, control 7 7 . 7 %), but partially by casein (3.5.9 %). Motilin is present in human milk. In the newborr~, motilin's digestion may be sufficiently retarded to allow luminal motilin to exert a biological effect.
control
small tumor
Whole body turnover Gin 1758 ± 277 2348 ± turnover protein 147 ± 44 244 ± Hindquarter Gin release 84 ± 53 348 ± net release (Phe) 0.9 ± 3.2 19 ± prot.synthesis 25 ± 19 25 ± orot.breakdown 24 ± 17 44 ± M-WU; "p<0.05vs control';datain nmol/10Og bw/min.
285 59~ 76= 6= 11 10
larae turrtQr
4316 ± 320= 313 ± 313a 191 7 48 55
± ± ± =
52 2 18 18
Conclusion Tumor growth is associated with increased Gin turnover. In small tumor bearing rats is associated with increased muscle protein breakdown and Gin production. However, in large tumor bearing rats muscle protein degrader!on and Gin production remain unchanged. This possibly reflects a decreased metabolic capacity to adapt to surgical stress seen in cancer patients.
THE EFFECT O F PARTIALLY HYDROLYZED GUAR G U M (PHGG) O N THE USE O F LAXATNE AGENTS IN A N ELDERLY NURSING H O M E POPULATION. M.H. DeLegge$, S.C. Marx', S.M. Gohman*, P.G. Patrick:t:,N.A. Greenberg*, :l:Medicol College of Virginia, Richmond VA, "North Ridge Care Center, Minneapolis MN, *Sondoz Nutrition, Minneapolis, MN. Background: Constipation occurs in 20-30% of the general elderly population and up to 60% of ~e institutionalized elderly. Non-fiber laxative agents are the most commonly used method to control constipation in the institutionalized elderly. Aim: The purpose Of this study was to evaluate the influence of a soluble dietary fiber supplement (PHGG), on laxative use and incidence of constipation in an institutionalized elderly (>65 years) population. Methods: We recruited 21 aled residents from 2 nursing homes who required daily laxatives for constipation. Laxative use, number and consistency of stools, ease and completeness of bowel movementsand degree of flatulence were monitored during a 3 week baseline phase and subsequent 5 week fiber phase. After base no, subjects were gradually transitioned on to 8-12 grams of PHGG per day, and laxative doses were cut in half and then'eliminated. The nursing staff mixed the PHGG fiber with 4 oz of juice or water and administered it to the residentsTID. No other dietary changes were made. Subjects remained on the fiber for 5 weeks and were not allowed any laxatives unless they met constipation criteria, defined .as no bowel movement for 3 consecutive days. Results: Sixteenresidents (mean age 83 years) completed the 8 week trial and showed a significant reduction in laxative use during the fiber supplemented phase (p<.0001). There we~'eno significant differences in mean number, consistency or ease of bowel movementsduring the baseline or fiber supplemented phase. Completenessof evacuation was also judged by residents to be similar between phases. During the fiber phase, residents reported a significantly greater incidence of moderate flatulence (p<.05). Conclusions: Dai~y intake of PHGG which provided 8-12 grams of soluble dietary fiber maintained daily bowel movements and significantly decreased laxative use in an elderly population.
THE ROLE OF CAPSAICIN-SENSITIVE SENSORY NEURONS AND NITRIC OX IDE IN REGULAT ION OF GASTR IC MUCOSAL GROWTH. A. Dembinski, Z. Warzecha, P. Ceranowloz S.J. Konturek. Inst. Physiol. Univ. Sch Med., KPakow, Poland. Capsaicln and nitric oxide (NO) cause potent vasorelaxat ion which is important in Eastroprotect lye act Lvity against damage but the mechanisms underlyin E these effects have not been elucidated. This study investigated the influence of capsaicin-induced functional ablation of afferent neurons and inhibition of NO production on the gastric mucosa growth in normal conditions, after 48 h fasting and subsequent refeeding. We found that ablation of sensory neurons by capsaiein pretreatment (I00 mE/kg over 3 days) reduced by around 45Y, the gastric mucosal blood flow ( ~ F ) in normal feed and refed rats while by 157, only in fasted animals. This drop in HBF after capsaicin-induced denervation was accompanied by significant decrease in DNA synthesis {by 40 ~ in control group and 35 Y. in refed rats} and was less pronounced in the group of fasted rats (23 %). Ablation of sensory neurons resulted in a significant decrease in the stomach weight, RNA, and protein content in regularly feed and refed but not 48 h fasted ani~is. Treatment with NS-nitro-L-arginine {L-NNA; 2x20 mg/kg daily s.c.), a selective blocker of NO synthase, significantly suppressed the MBF in all three groups of animals tested but this suppression was less pronounced when compared to capsaicin pretreatment. This MBF inhibitory effect of L-NNA on the gastric mucosa was fully antagonized by L-arginine (2xlO0 mg/kE daily s.c. ). L-NNA injection s.c. significantly reduced the DNA synthesis, RNA, and DNA content in all tested groups of rats. This inhibition was reversed by the addition of L-argznzne. The combination of capsaicln and L-NNA decreased the~ MBF significantly and the inhibition was stroI~ger than the effect o f each substance given alone. In groups of rats E~ven neurotoxic dose of capsaicin together with L-NNA all growth parameters were significantly reduced. We conclude that both the capsaicin- induced denervat ion and the suppression of endogenous NO by L-NNA inhibit the growth of the gastric mucosa by the mechanism involving, at least in part, the suppression of gastric mucosal blood flow.
AGA ABSTRACTS
GASTROENTEROLOGY, Vol. 108, No. 4
INCREASED WHOLE BODY GLUTAMINE TURNOVER iN CANCER IS NOT MATCHED BY INCREASED HINDQUARTER GLUTAMINE RELEASE Lde Blaauw, NEP Deutz, MF von Meyenfeldt, Dept of Surgery, Fac II, Univ Limburg. Maastricht,The Nether!ands.
MOTILIN IN HUMAN M I L K : IDENTIFICATION AND STABILITY DURING DIGESTION. P.De Clerca, S.Springer', T,L,Peeters. Gut Hormone Lab, K.U.Leuven, Leuven, Belgium and "Paediatric Unit, University Hospital, Leipzig, Germany.
Glutamine (Gin) is mainly produced by muscle. Cancer cells consume Gin at a high rate for energy ~nd nucleotide production and may disturb Gin interorgan metabolism. Aim of this study was to see whether whole body Gin and protein metabolism were matched by sufficient Gin release of muscle tissue. Methods A MCA-induced sarcoma was implanted subcutaneously in Lewis rats (±250 gr). Rats were studied when the tumor was 5-15% (ST) or 15-25% (L'r) of the body weight. Control rats were sham implanted. Under anesthesia a constant infusion of para-aminohippuric acid, L-[3,4-3H]-GIn and L-[2,6-3H]Phenylalanine was given. At steady state, hindquarter bloodfiow, arterial and venous substrate concentrations and amino acid specific activity were measured to calculate whole body Gin and protein turnover, hindquarter Gin release and hindquarter muscle protein turnover, Results No anorexia occurred and carcass weight was not significantly different between the groups. Arterial Gin levels decreased from 657±26 (control) to 611±22 (ST) to 558±13 pM (P<0.05) in the LT group. Table Whole body Gin turnover increased in the LT group. Protein turnover increased in the ST and LT group. Hindquarter release of glutamine increased in the ST group but decreased again in the LT group. A net protein loss was seen (Phe release) in the ST possible due to increased protein breakdown rates with unchanged protein synthesis rates. Net protein breakdown was unchanged in the LT group.
The presence in human milk of several brain-gut peptides and of peptide g r o w t h factors has been documented and a role o f these peptides in early development has been suggested. We have studied the presence and stability of motUin in human milk. Milk and plasma samples were collected from 14 mothers, and motilin was measured by radioimmunoassay. Plasma levels were 416 ± 37 pg/ml. In 8 defatted milk samples the motilin level was 105 ± 14 pg]ml, in the 6 others levels were above i 0 0 0 pg/ml but dilution Curves were non-linear. After solid-ph~ise extraction milk levels were 108 ± 21 pg/ml in 13 samples, i n 1 sample the dilution curve w a s Still non-linear. The presence of motilin was certified by the partial purification of motilin from human milk. A 500 ml amount of human m i l k was defatted, absorbed on a Cls.column and eluted with 50% acetonitrile in 10 mM HCI. The eluate was tyophilized and subjected to gel chromatography and HPLC. In b o t h instances the peak of immune-reactivity eluted at the same position as human motilin. The stability of motilin after ingestion w a s studied by incubating 12sl-nlelS-porcine motilin with gastric a n d intestinal juice obtained from a newborn (diluted 1:10). Incubations were performed at 3 7 ° C at pH 1.8, 3.2 and 5.8 for the gastric fluid and at pH 7.4 for duodenal fluid. Afte r different t i m e intervals ( 5 , 10, 20, 30 m i n ) i n t a c t motilin Was precipitated with trichloroacetic acid, and the radioactivity of t h e supernatans was determined: Motilin was rapidly degraded by gastric juice. The breakdown was greatest at pH 3.2 (77.8 % after 30 min) and lowest a t 15H 5 . 8 ( 3 9 . 1 % ) , the pH after milk feeding in neonates. Degradation by intestinal juice at pH 7.4 was also very rapid (73.9 % ). Human milk and BSA inhibited partially, casein inhibited totally the gastric digestion at pH 3.2 (36.6%, 53.2% and 5 . 0 % d e g r a d a t i o n after 30 mm, respectively). Digestion by intestinal juice was not affected by human milk and BSA (77.2 and 80.2 %, control 7 7 . 7 %), but partially by casein (3.5.9 %). Motilin is present in human milk. In the newborr~, motilin's digestion may be sufficiently retarded to allow luminal motilin to exert a biological effect.
control
small tumor
Whole body turnover Gin 1758 ± 277 2348 ± turnover protein 147 ± 44 244 ± Hindquarter Gin release 84 ± 53 348 ± net release (Phe) 0.9 ± 3.2 19 ± prot.synthesis 25 ± 19 25 ± orot.breakdown 24 ± 17 44 ± M-WU; "p<0.05vs control';datain nmol/10Og bw/min.
285 59~ 76= 6= 11 10
larae turrtQr
4316 ± 320= 313 ± 313a 191 7 48 55
± ± ± =
52 2 18 18
Conclusion Tumor growth is associated with increased Gin turnover. In small tumor bearing rats is associated with increased muscle protein breakdown and Gin production. However, in large tumor bearing rats muscle protein degrader!on and Gin production remain unchanged. This possibly reflects a decreased metabolic capacity to adapt to surgical stress seen in cancer patients.
THE EFFECT O F PARTIALLY HYDROLYZED GUAR G U M (PHGG) O N THE USE O F LAXATNE AGENTS IN A N ELDERLY NURSING H O M E POPULATION. M.H. DeLegge$, S.C. Marx', S.M. Gohman*, P.G. Patrick:t:,N.A. Greenberg*, :l:Medicol College of Virginia, Richmond VA, "North Ridge Care Center, Minneapolis MN, *Sondoz Nutrition, Minneapolis, MN. Background: Constipation occurs in 20-30% of the general elderly population and up to 60% of ~e institutionalized elderly. Non-fiber laxative agents are the most commonly used method to control constipation in the institutionalized elderly. Aim: The purpose Of this study was to evaluate the influence of a soluble dietary fiber supplement (PHGG), on laxative use and incidence of constipation in an institutionalized elderly (>65 years) population. Methods: We recruited 21 aled residents from 2 nursing homes who required daily laxatives for constipation. Laxative use, number and consistency of stools, ease and completeness of bowel movementsand degree of flatulence were monitored during a 3 week baseline phase and subsequent 5 week fiber phase. After base no, subjects were gradually transitioned on to 8-12 grams of PHGG per day, and laxative doses were cut in half and then'eliminated. The nursing staff mixed the PHGG fiber with 4 oz of juice or water and administered it to the residentsTID. No other dietary changes were made. Subjects remained on the fiber for 5 weeks and were not allowed any laxatives unless they met constipation criteria, defined .as no bowel movement for 3 consecutive days. Results: Sixteenresidents (mean age 83 years) completed the 8 week trial and showed a significant reduction in laxative use during the fiber supplemented phase (p<.0001). There we~'eno significant differences in mean number, consistency or ease of bowel movementsduring the baseline or fiber supplemented phase. Completenessof evacuation was also judged by residents to be similar between phases. During the fiber phase, residents reported a significantly greater incidence of moderate flatulence (p<.05). Conclusions: Dai~y intake of PHGG which provided 8-12 grams of soluble dietary fiber maintained daily bowel movements and significantly decreased laxative use in an elderly population.
THE ROLE OF CAPSAICIN-SENSITIVE SENSORY NEURONS AND NITRIC OX IDE IN REGULAT ION OF GASTR IC MUCOSAL GROWTH. A. Dembinski, Z. Warzecha, P. Ceranowloz S.J. Konturek. Inst. Physiol. Univ. Sch Med., KPakow, Poland. Capsaicln and nitric oxide (NO) cause potent vasorelaxat ion which is important in Eastroprotect lye act Lvity against damage but the mechanisms underlyin E these effects have not been elucidated. This study investigated the influence of capsaicin-induced functional ablation of afferent neurons and inhibition of NO production on the gastric mucosa growth in normal conditions, after 48 h fasting and subsequent refeeding. We found that ablation of sensory neurons by capsaiein pretreatment (I00 mE/kg over 3 days) reduced by around 45Y, the gastric mucosal blood flow ( ~ F ) in normal feed and refed rats while by 157, only in fasted animals. This drop in HBF after capsaicin-induced denervation was accompanied by significant decrease in DNA synthesis {by 40 ~ in control group and 35 Y. in refed rats} and was less pronounced in the group of fasted rats (23 %). Ablation of sensory neurons resulted in a significant decrease in the stomach weight, RNA, and protein content in regularly feed and refed but not 48 h fasted ani~is. Treatment with NS-nitro-L-arginine {L-NNA; 2x20 mg/kg daily s.c.), a selective blocker of NO synthase, significantly suppressed the MBF in all three groups of animals tested but this suppression was less pronounced when compared to capsaicin pretreatment. This MBF inhibitory effect of L-NNA on the gastric mucosa was fully antagonized by L-arginine (2xlO0 mg/kE daily s.c. ). L-NNA injection s.c. significantly reduced the DNA synthesis, RNA, and DNA content in all tested groups of rats. This inhibition was reversed by the addition of L-argznzne. The combination of capsaicln and L-NNA decreased the~ MBF significantly and the inhibition was stroI~ger than the effect o f each substance given alone. In groups of rats E~ven neurotoxic dose of capsaicin together with L-NNA all growth parameters were significantly reduced. We conclude that both the capsaicin- induced denervat ion and the suppression of endogenous NO by L-NNA inhibit the growth of the gastric mucosa by the mechanism involving, at least in part, the suppression of gastric mucosal blood flow.